Load cell attachment structure

ABSTRACT

This load cell attachment structure includes a male screw which is formed on a load sensing part of the load cell, a nut which attaches the load cell to the attachment plate by engaging with the male screw, and a wave washer which is disposed between the attachment plate and the nut.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a load cell attachment structure.

Priority is claimed on Japanese Patent Application No. 2004-259502,filed Sep. 7, 2004, and on Japanese Patent Application No. 2004-259503,filed Sep. 7, 2004, the content of which is incorporated herein byreference.

2. Description of Related Art

In order to control operating and the like of an air bag system when acollision of a vehicle happens, a load cell which measures load actingon a seat is mounted on the vehicle. Then, it is determined whether anoccupant is seated or not, and whether the occupant who is seated is anadult or a child, and the like.

For example, there is a system which includes stud bolts projectingabove, which is disposed on the front and rear of sliders of bilateralseat rails, a plate member which is fixed on the stud bolts and a seatframe. One end of the plate member is fixed on a tip of the stud boltswhich go through holes of the seat frame, and the other end of the platemember is fixed on the seat frame (refer to U.S. Pat. No. 6,161,891). Inthe reference, amount of deformation of the plate member is measured.

Also, as shown in FIG. 7, there is a system in which a male screw 102 isdisposed on a load sensing part 101 of a load cell 100, the load cell100 is attached to a slider 103 of a seal rail facing upward toward theload sensing part 101, and an attachment plate 104 of a seat frame isattached to the load cell 100 by engaging a nut 105 with the male screw102. In this system, when the attachment plate 104 is attached to theload sensing part 101 by fastening the nut 105 to the male screw 102tightly, if only the attachment plate 104 of the seat frame warps orinclines slightly due to a minor accident of the vehicle or the like,the load cell 100 measures slight loads are caused by the warp or theincline. As a result, the load cell 100 cannot measure loads accurately.Accordingly, as shown in FIG. 8, it is proposed that clearance whichallows warp or the incline of the attachment plate 104 be formed betweenthe nut 105 and the load sensing part 101 by disposing a collar 106between the nut 105 and the load sensing part 101. However, in thissystem, a fastening force along the longitudinal direction of the malescrew 102 acts on the load sensing part 101 through the collar 106. As aresult, the load cell 100 senses undesired load. In other words, driftforce along the axis is caused on the load cell 100.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a load cellattachment structure capable of preventing a load cell from sensingundesired loads which are caused by warp or a incline of the attachmentplate, and as a result, load cell can measure loads accurately.

A load cell attachment structure of the present invention for attachinga load cell to an attachment plate includes: a first fastening partwhich is formed on a load sensing part main body of the load cell; asecond fastening part which attaches the load cell to the attachmentplate by engaging with the first fastening part; and an elastic bodywhich is disposed between the attachment plate and the second fasteningpart.

According to the present invention, since the elastic body is disposedbetween the attachment plate and the second fastening part, if theattachment plate warps or inclines, such wrap or incline is absorbed bydeformation of the elastic body. Therefore, a load sensing part of theload cell does not sense an undesired load which is caused by the warpor the incline of the attachment plate. As a result, it is possible tomeasure loads which act on the load sensing part exactly.

It is preferable that the load cell attachment structure further includea washer part which covers the load sensing part, and is disposedbetween the load sensing part and the attachment plate, and a collarpart which is disposed between the washer part and the second fasteningpart, wherein a length of the collar part along an axis thereof islonger than a thickness of the attachment plate.

According to the present invention, a clearance which absorbs the wrapor incline of the attachment plate is appropriately formed between thewasher part and the second fastening part by the collar part. Inaddition, the fastening force which is introduced through the collarpart is dispersed on the load sensing part evenly, by the washer part.Therefore, the load cell does not sense an undesired load which iscaused by the warp or the incline of the attachment plate, and thefastening force. As a result, it is possible to measure loads which acton the load sensing part exactly.

It is preferable in the load cell attachment structure of the presentinvention, that the first fastening part be a male screw, the secondfastening part be a nut, the elastic body be disposed between theattachment plate and the nut, and the collar part be disposed betweenthe washer part and the nut. Alternatively, it is preferable in the loadcell attachment structure of the present invention, that the firstfastening part be a female screw, the second fastening part be a bolt,the elastic body be disposed between the attachment plate and a top ofthe bolt, and the collar part be disposed between the washer part andthe top of the bolt.

It is preferable for the load cell attachment structure of the presentinvention that the collar part be formed as a single body with thewasher part.

According to the present invention, since the collar part is formed as asingle body with the washer part, it is possible to reduce quantity ofparts and time in assembling.

A load cell attachment structure of the present invention for attachinga load cell to an attachment plate includes: a first fastening partwhich is formed on a load sensing part main body of the load cell; asecond fastening part which attaches the load cell to the attachmentplate by engaging with the first fastening part; a washer part whichcovers the load sensing part, and is disposed between the load sensingpart and the attachment plate; and a collar part which is disposedbetween the washer part and the second fastening part, wherein a lengthof the collar part along an axis thereof is longer than a thickness ofthe attachment plate.

According to the present invention, a clearance which absorbs the wrapor incline of the attachment plate is appropriately formed between thewasher part and the second fastening part by the collar part. Inaddition, the fastening force which is introduced through the collarpart is dispersed on the load sensing part evenly by the washer part.Therefore, the load cell does not sense an undesired load which iscaused by the warp or incline of the attachment plate, and dispersion ofinitial values of the load cell, which is caused by difference infastening torque is not caused. As a result, it is possible to measureloads which act on the load sensing part exactly.

It is preferable in the load cell attachment structure of the presentinvention that the first fastening part be a male screw, the secondfastening part be a nut, and the collar part be disposed between thewasher part and the nut. Alternatively, it is preferable in the loadcell attachment structure of the present invention, that the firstfastening part be a female screw, the second fastening part be a bolt,and the collar part be disposed between the washer part and a top of thebolt.

It is preferable in the load cell attachment structure of the presentinvention that the collar part be formed as a single body with thewasher part.

According to the present invention, since the collar part is formed as asingle body with the washer part, it is possible to reduce the quantityof parts and time in assembling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the seat of a vehicle to which aload cell attachment structure according to the present invention isapplied.

FIG. 2 is sectional view of the load cell attachment structure accordingto the present invention.

FIG. 3 is sectional view of the load cell attachment structure accordingto the present invention, in particular, showing a state in which theattachment plate inclines.

FIG. 4 is sectional view of first variant of the load cell attachmentstructure according to the present invention.

FIG. 5 is sectional view of second variant of the load cell attachmentstructure according to the present invention.

FIG. 6 is sectional view of third variant of the load cell attachmentstructure according to the present invention.

FIG. 7 is sectional view of a conventional load cell attachmentstructure.

FIG. 8 is sectional view of another conventional load cell attachmentstructure.

DETAILED DESCRIPTION OF THE INVENTION

A description is given below of a load cell attachment structureaccording to one embodiment of the present invention with reference tothe drawings.

FIG. 1 shows the right half side of an occupant's seat 11 of a vehicle.A seat frame 11 12 which composes a skeletal structure of the seat 11 issupported on a pair of seat rails 14 so as to be capable of sliding inthe lengthwise direction of the vehicle. The seat rails 14 are spacedapart from each other in the widthwise direction of the vehicle, and arefixed on a floor panel 13 of the vehicle. Note that, only one of thepair of seat rails 14 is shown in FIG. 1.

The seat rail 14 is composed of a rail main body 20 and a slider 21. Therail main body 20 extends along the lengthwise direction of the vehicle,and is fixed on the floor panel 13. The slider 21 extends along thelengthwise direction of the vehicle, and is supported on the rail mainbody 20 so as to be capable of sliding in the lengthwise direction ofthe vehicle.

Load cells 25 which measure loads, are respectively mounted on a frontend part and a rear end part of the slider 21. Attachment plates 26spaced apart from each other in the widthwise direction of the vehicleare fixed on a floor panel 13 of the vehicle.

The pair of attachment plates 26 is disposed under the seat frame 12.One of the pair of attachment plates 26 is disposed on the right side ofthe seat 11, and is attached to the load cells 25 mounted on the slider21, the other of the pair of attachment plates 26 is disposed on theleft side of the seat 11, and is attached the load cells 25 mounted onthat slider 21.

The load cell attachment structure of this embodiment includes a malescrew 36 (first fastening part) which is formed on a load sensing part38 cell main body 35 of the load cell 25, a nut 50 (second fasteningpart) which attaches the load cell 25 to the attachment plate 26 byengaging with the male screw 36, and a wave washer 47 (elastic body)which is disposed between the attachment plate 26 and the nut 50.

As shown in FIG. 2, the load cell 25 has a base plate 31 which extendsin one direction. The base plate 31 is disposed along the lengthwisedirection of the vehicle the left-right direction in FIG. 2. A frontpart and a rear part of the base plate 31 are attached to the slider 21with bolts 32.

As in the above description, the load cell 25 is attached to the slider21 through the base plate 31. A load cell main body 35 of the load cell25 is fixed on the center of an upper surface of the base plate 31. Theload cell main body 35 is formed as a substantially column-like shape,the direction of load of the load cell main body 35 being in thevertical direction. The male screw 36 is fixed on the center of an uppersurface of the load cell main body 35 so as to be protruding upward.

The load sensing part 38 is the upper surface of the load cell main body35 with the exception of the male screw 36. In other words, the malescrew 36 is formed on the load sensing part 38 cell main body 35 of theload cell 25. The load cell main body 35 warps slightly when subjectedto downward load from the load sensing part 38, and measures loadcorresponding to the amount of the warp.

A washer 40 is mounted on the load cell main body 35. The washer 40 iscomposed of a washer part 41 and a collar part 42. The washer part 41 isformed as a disk shape, and has a circular hole at the center thereof.The external diameter of the washer part 41 is the same as the externaldiameter of the load sensing part 38. The collar part 42 is formed as acylinder shape, and the external diameter of the collar part 42 is lessthan the external diameter of the washer part 41. The collar part 42 isdisposed on the washer part 41 so as to protrude upward from the washerpart 41, and is formed as a single body with the washer part 41 so thatan axis of the washer part 41 and an axis of the collar part 42coincide. Since the axis of the washer part 41 and the axis of thecollar part 42 coincide, a penetration hole 43 is formed on the washerpart 40. The internal diameter of the penetration hole 43 is greaterthan a external diameter of the male screw 36.

The male screw 36 is inserted into the penetration hole 43, and thewasher part 41 contacts the load sensing part 38, and thus the washer 40is mounted on the load cell main body 35. In this condition, the wholeof the load sensing part 38 is covered by the washer part 41. Further,since a top end of the male screw 36 of the load cell 25 protrudesupward from the washer 40, the upper surface of the washer part 41, theupper end surface of the collar part 42, and the upper surface of theload sensing part 38 are parallel with each other. It is preferable thatthe external diameter of the washer part 41 be the same as the externaldiameter of the load sensing part 38, or be greater than the externaldiameter of the load sensing part 38.

The male screw 36 is inserted into the collar part 42, and the collarpart 42 into which the male screw 36 is inserted is inserted into anattachment hole 45 which is formed on the attachment plate 26, and thusthe attachment plate 26 is mounted on the washer part 41. Note that thelength of the collar part 42 in the vertical direction is greater thanthe thickness of the attachment plate 26, and accordingly a top endsurface of the collar part 42 protrudes upward from the attachment plate26 contacting the washer part 41.

The wave washer 47 is mounted on the attachment plate 26, which contactsthe upper surface of the wave washer 47. The wave washer 47 is formed asa ring shape, and the external diameter of the wave washer 47 is greaterthan the external diameter of the washer part 41. The collar part 42protruding upward from the attachment hole 45 of the attachment plate 26is inserted into a center hole of the wave washer 47. When the wavewasher 47 is not deformed, the thickness of the wave washer 47 isgreater than a difference between the length of the collar part 42 inthe vertical direction and the thickness of the attachment plate 26, andwhen the wave washer 47 is deformed, the thickness of the wave washer 47is less than the difference between the length of the collar part 42 inthe vertical direction and the thickness of the attachment plate 26.Therefore, when the wave washer 47 is mounted on the attachment plate 26and is not deformed, a highest point of an upper surface of the wavewasher 47 is positioned above the upper end surface of the collar part42.

The washer 49 is mounted on the wave washer 47. The male screw 36protruding upward from the penetration hole 43 of the washer 40 isinserted into a center hole of the washer 49. The internal diameter ofthe washer 49 is greater than the external diameter of the male screw36, and is less than the external diameter of the collar part 42. Theexternal diameter of the washer 49 is approximately the same as theexternal diameter of the wave washer 47.

The nut 50 is thread-engaged with the male screw 36. The nut is fastenedat predetermined torque. Therefore, the washer 49 and the washer 40 aresandwiched to be fixed between the nut 50 and the load cell 25. That is,a lower surface of the nut 50 closely contacts an upper surface of thewasher 49. Further, a lower surface of the washer 49 closely contactsthe collar part 42 of the washer 40, and a lower surface of the washerpart 41 of the washer 40 closely contacts an upper surface of the loadsensing part 38 of the load cell main body 35. In this condition, sincethe washer 49 and the washer 40 are close to each other, the wave washer47 which is sandwiched between the washer 40 and washer 49 deformselastically. When the wave washer 47 deforms elastically, the attachmentplate 26 is pushed against the washer part 41 which is positioned underthe attachment plate 26 due to the elastic force of the wave washer 47.

The load cell 25 is attached to the attachment plate 26 by the nut 50being thread-engaged with the male screw 36. Further, the whole of theload sensing part 38 is covered by the washer part 41, and the washerpart 41 is sandwiched between the load sensing part 38 and theattachment plate 26. Furthermore, the collar part 42 which is thickerthan the thickness of the attachment plate 26 is disposed between thewasher part 41 and the nut 50. Moreover, the wave washer 47 is disposedbetween the attachment plate 26 and the nut 50.

As in the above description, four corners of the seat 11, that is thefront part and the rear part of the pair of the seat frames 12 aresupported by the seat rails 14 which are spaced apart from each other inthe widthwise direction by way of the four load cells 25. Load which isadded onto the seat 11 is introduced from the seat frame 12 into theload sensing part 38 through the washer part 41. The load cell main body35 warps slightly due to being introduced load from the load sensingpart 38, and generates an electrical charge corresponding to the loadwhich is introduced through the washer part 41. The electrical charge ismeasured by a control section (not shown in the figures).

Based upon the load which is measured by the four load cells 25, thecontrol section makes a decision as to whether or not a occupant isseated on the seat 11. Also, the control section makes a decision as towhether the occupant is an adult or a child. Further, based upon thedecision, the control section controls the way of operating and the likeof the air bag system, when a collision of the vehicle happens.

According to the load cell attachment structure of above describedembodiment, since the wave washer 47 is disposed between the attachmentplate 26 and nut 50, as shown in FIG. 3, if the attachment plate 26warps or inclines, such warp or incline is absorbed by the deformationof the wave washer 47. Therefore, the load cell 25 does not sense anundesired load (in other words, “offset load”) caused by the warp orincline of the attachment plate 26 or imperfect assembly. Further, theweight of the seat 11 and of the occupant on the seat 11 is introducedfrom the attachment plate 26 to the load sensing part 38 through thewasher 40. As a result, it is possible to measure load which acts on theload sensing part 38 exactly.

As shown in FIG. 3, the load cell attachment structure of thisembodiment includes the washer 40 which is composed of the washer part41 and the collar part 42. The washer part 41 substantially covers theload sensing part 38, and is sandwiched between the load sensing part 38and the attachment plate 26. The collar part 42 is disposed between thewasher part 41 and the nut 50, the length of the collar part 42 in theaxial direction being greater than the thickness of the attachment plate26. In other words, the length of the collar part 42 in the axialdirection is greater than the sum of the thickness of the attachmentplate 26 and the minimum thickness of the wave washer 47.

Due to this, a clearance which absorbs the wrap or incline of theattachment plate 26 is appropriately formed between the nut 50 and thewasher part 41 by the collar part 42. In addition, the fastening forcewhich is introduced through the collar part 42 is dispersed on the loadsensing part 38 evenly by the washer part 41. Therefore, the load cell26 25 does not sense an undesired load which is caused by the warp orincline of the attachment plate 26 due to a minor collision of thevehicle or the fastening force. As a result, it is possible to measureloads exactly.

In addition, the fastening force which is introduced through the collarpart 42 is dispersed on the load sensing part evenly by the washer part41. Therefore, the load cell 25 does not sense an undesired load (inother words, “drift force along the axis”) which is caused by thefastening force, and dispersion of initial values of the load cellcaused by difference in fastening torque can be reduced. As a result, itis possible to measure load exactly. That is, when the washer 40 is acollar only, in the total sensing range of the load sensor 25, the rangedefined by counting out the weight of the seat as well as drift from thefastening force becomes the range that can be used to sense the weightof the occupant. However, when the washer 40 is provided with the washerportion 41 and the collar portion 42, in the total sensing range of theload sensor 25, the range defined by counting out only the weight of theseat becomes the range that can be used to sense the weight of theoccupant. Accordingly, the effective sensing range of the sensor becomesextremely wide.

Since the wave washer 47 is disposed between the attachment plate 26 andthe nut 50, if the attachment plate 26 does not warp or incline, or ifthe attachment plate 26 warps, the wave washer 47 deforms correspondingto the warp or incline. Therefore, it is possible to reduce the backlashof the attachment plate 26 which is disposed between the washer 49 andthe washer part 41.

Since the collar part 42 is formed as a single body with the washer part41, it is possible to reduce the quantity of parts and time in assembly.Naturally, the collar part 42 and the washer part 41 can also beseparate. Note that, if the load cell 25 can measure loads exactlywithout the dispersion of the fastening force over the load sensing part38, as shown in FIG. 4, the washer 40 may include only the collar part42 without the washer part 41.

The load cell attachment structure of this embodiment may includeanother elastic body instead of the wave washer 47. For example, asshown in FIG. 5, a plate-spring shape washer 52 may be disposed betweenthe nut 50 and the washer 41. The washer 52 is composed of a flat platepart 53 with a ring shape and a tapered part 54 which is disposed on theoutside edge of the flat plate part 53. The tapered part 54 inclineswith respect to the flat plate part 53. The flat plate part 53 closelycontacts the lower surface of the nut 50 and the upper end surface ofthe collar part 42, and an outside edge of the tapered part 54 closelycontacts the attachment plate 26.

Further, as shown in FIG. 6, a plate-spring 62 which is sandwichedbetween washers 63, 64 may be disposed between the nut 50 and the washer40. The plate-spring 62 is composed of a flat plate part 60 with a ringshape and a tapered part 61 which is disposed on the outside edge of theflat plate part 60. The tapered part 61 inclines with respect to theflat plate part 60. The washer 63 is disposed between the plate-spring62 and the nut 50, and the washer 64 is disposed between theplate-spring 62 and the collar part 42. The external diameter of thewasher 63 is less than the external diameter of the washer 64, and theexternal diameter of the plate-spring 62 is less than the externaldiameter of the washer 64. The washer 63 closely contacts the lowersurface of the nut 50, and the washer 64 closely contacts the upper endsurface of the collar part 42. Further, an outside edge of the taperplate part 61 closely contacts the attachment plate 26. A resinous cover66 is disposed on an inside edge of the attachment hole 45 of theattachment plate 26. The cover 66 prevents the inside edge of theattachment hole 45 from contacting the washer 40.

In the above embodiment, the structure in which the load cell 25 isattached to the attachment plate 26 by the male screw 36 being disposedon the load sensing part 38 of the load cell 25, and the nut 50 beingthread-engaged with the male screw 36, is explained. However, astructure in which the load cell 25 is attached to the attachment plate26 by a female screw being disposed on the load sensing part 38 of theload cell 25, and a bolt being thread-engaged with the female screw, maybe applied. In this structure, the bolt is inserted into the penetrationhole 43, and the collar part 42 of the washer 40 is disposed between thewasher part 41 and a top of the bolt. Also, the wave washer 47 isdisposed between the attachment plate 26 and the top of the bolt.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the spirit or scope of the present invention.Accordingly, the invention is not to be considered as being limited bythe foregoing description, and is only limited by the scope of theappended claims.

1. A load cell attachment structure for attaching a load cell to anattachment plate, the load cell including a main body and a load sensingpart, the load cell attachment structure comprising: a first fasteningpart which is formed on a load sensing part the main body of the loadcell; a second fastening part which attaches the load cell to theattachment plate by engaging with the first fastening part; an elasticbody which is disposed between the attachment plate and the secondfastening part; and a washer part which entirely covers the load sensingpart, and is disposed between the attachment plate and the load sensingpart.
 2. A load cell attachment structure according to claim 1, furthercomprising: a collar part which is disposed between the washer part andthe second fastening part, wherein a length of the collar part along anaxis thereof is longer than a thickness of the attachment plate.
 3. Aload cell attachment structure according to claim 2, wherein the firstfastening part comprises a male screw, the second fastening partcomprises a nut, the elastic body is disposed between the attachmentplate and the nut, and the collar part is disposed between the washerpart and the nut.
 4. A load cell attachment structure according to claim2, wherein the collar part is formed as a single body with the washerpart.
 5. A load cell attachment structure for attaching a load cell toan attachment plate, the load cell including a main body and a loadsensing part, the load cell attachment structure comprising: a firstfastening part which is formed on a load sensing part the main body ofthe load cell; a second fastening part which attaches the load cell tothe attachment plate by engaging with the first fastening part; a washerpart which entirely covers the load sensing part, and is disposedbetween the load sensing part and the attachment plate; and a collarpart which is disposed between the washer part and the second fasteningpart, wherein a length of the collar part along an axis thereof islonger than a thickness of the attachment plate.
 6. A load cellattachment structure according to claim 5, wherein the first fasteningpart comprises a male screw, the second fastening part comprises a nut,and the collar part is disposed between the washer part and the nut. 7.A load cell attachment structure according to claim 5, wherein thecollar part is formed as a single body with the washer part.
 8. A loadcell attachment structure for attaching a load cell to an attachmentplate, the load cell including a main body and a load sensing part, theload cell attachment structure comprising: a male screw which is formedon a load sensing part the main body of the load cell and which isinserted into an attachment hole formed in the attachment plate; a nutwhich attaches the load cell to the attachment plate by engaging withthe male screw; an elastic body which is disposed between the attachmentplate and the nut fastened on the male screw; and a washer having awasher part and a collar part and which is disposed between the loadsensing part and the attachment plate, in which the washer part coversall of the load sensing part and contacts the load sensing part, and thecollar part is disposed between the washer part and the nut, wherein themale screw is inserted into the collar part, the collar part is insertedinto the attachment hole, the length of the collar part along an axisthereof is longer than a thickness of the attachment plate to have aspace between the nut and the attachment plate, and the elastic bodyhaving a thickness greater than the space is disposed between theattachment plate and the nut, and the nut is engaged with the male screwuntil the nut contacts the collar part.
 9. A load cell attachmentstructure for attaching a load cell to an attachment plate, the loadcell including a main body and a load sensing part, the load cellattachment structure comprising: a male screw which is formed on a loadsensing part the main body of the load cell and which is inserted intoan attachment hole formed in the attachment plate; a nut which attachesthe load cell to the attachment plate by engaging with the male screw; aplate-spring which is composed of a flat plate part and a tapered partdisposed on the outside edge of the flat plate part and which isdisposed between the attachment plate and the nut fastened on the malescrew to push the attachment plate to the load sensing part; and, awasher having a washer part and a collar part and which is disposedbetween the load sensing part and the attachment plate, in which thewasher part contacts the load sensing part, and the collar part isdisposed between the washer part and the nut; wherein the flat platepart of the plate spring is disposed between the collar part and thenut.
 10. The load cell attachment structure according to claim 9,wherein an elastic cover is disposed on an edge of the attachment hole.11. The load cell attachment structure according to claim 10, wherein aspace is formed between the elastic cover and the collar part.
 12. Theload cell attachment structure of claim 10, wherein the elastic cover isdisposed between the attachment plate and the washer part.
 13. The loadcell attachment structure according to claim 9, wherein a second washeris disposed between the flat plate part and the collar part.
 14. Theload cell attachment structure according to claim 13, wherein a thirdwasher is disposed between the nut and the flat plate part, and an outerdiameter of the third washer is larger than that of the second washer.15. The load cell attachment structure according to claim 2, wherein theelastic body is arranged at a periphery of the collar part.
 16. The loadcell attachment structure according to claim 4, wherein the elastic bodyis arranged at a periphery of the collar part.
 17. The load cellattachment structure according to claim 1, wherein the washer partcontacts the load sensing part.
 18. The load cell attachment structureaccording to claim 1, wherein an outer edge of the elastic body isfarther than a periphery of the main body of the load cell from thefirst fastening part arranged at a center of the main body.
 19. The loadcell attachment structure according to claim 1, wherein the washer partis larger in diameter than the load sensing part.
 20. The load cellattachment structure according to claim 1, wherein an outer edge of theelastic body is farther than a periphery of the main body of the loadcell from the male screw arranged at the center of the main body. 21.The load cell attachment structure according to claim 7, wherein theload cell warps when load downwardly acts on the load sensing part, andthereby the load acting on the load sensing part is measured by the loadcell.
 22. The load cell attachment structure according to claim 7,further comprising an elastic body which is disposed between the washerpart and the second fastening part.
 23. The load cell attachmentstructure according to claim 22, wherein the elastic body includes aninclination part.
 24. The load cell attachment structure according toclaim 5, wherein the washer part contacts the load sensing part.
 25. Theload cell attachment structure according to claim 5, wherein the loadcell warps when a load downwardly acts on the load sensing part, andthereby the load acting on the load sensing part is measured by the loadcell.
 26. The load cell attachment structure according to claim 5,further comprising an elastic body which is disposed between the washerpart and the second fastening part.
 27. The load cell attachmentstructure according to claim 26, wherein the elastic body includes aninclination part.
 28. The load cell attachment structure according toclaim 26, wherein a second washer is disposed between the collar partand a nut included in the second fastening part.
 29. The load cellattachment structure according to claim 26, wherein the elastic bodyincludes a bending part.
 30. The load cell attachment structureaccording to claim 26, wherein an end of the elastic body close to thesecond fastening part contacts a second washer.
 31. The load cellattachment structure according to claim 26, wherein the attachment plateincludes an attachment hole to which the first fastening part isinserted, and a cover is disposed between a hole portion and the collarpart.
 32. The load cell attachment structure according to claim 31,wherein the cover prevents the collar part from contacting an attachmenthole of an attachment plate.
 33. The load cell attachment structureaccording to claim 31, wherein the cover is an independent member fromthe elastic body.
 34. The load cell attachment structure according toclaim 31, wherein the cover comprises an insertion portion to beinserted to the attachment hole, and an extension partoutwardly-extending in a radial direction from the insertion portion.35. The load cell attachment structure according to claim 31, whereinthe elastic body includes a bending part.
 36. The load cell attachmentstructure according to claim 5, wherein a second washer is disposedbetween the collar part and a nut included in the second fastening part.37. The load cell attachment structure according to claim 5, furthercomprising an elastic body which is disposed between the attachmentplate and the second fastening part, wherein the elastic body includes abending part.
 38. The load cell attachment structure according to claim5, wherein the washer part is larger in diameter than the load sensingpart.
 39. The load cell attachment structure according to claim 5,further comprising an elastic body which is disposed between theattachment plate and the second fastening part, wherein an end of theelastic body close to the second fastening part contacts a secondwasher.
 40. The load cell attachment structure according to claim 5,further comprising an elastic body which is disposed between theattachment plate and the second fastening part, wherein the elastic bodyis arranged at a periphery of the collar part.
 41. The load cellattachment structure according to claim 5, further comprising an elasticbody which is disposed between the attachment plate and the secondfastening part, wherein an outer edge of the elastic body is fartherthan a periphery of the main body of the load cell from the male screwarranged at the center of the main body.
 42. The load cell attachmentstructure according to claim 5, wherein the attachment plate includes anattachment hole to which the first fastening part is inserted, and acover is disposed between a hole portion and the collar part.
 43. Theload cell attachment structure according to claim 42, wherein the coverprevents the collar part from contacting an attachment hole of anattachment plate.
 44. The load cell attachment structure according toclaim 8, wherein the washer part contacts the load sensing part.
 45. Theload cell attachment structure according to claim 8, wherein an outeredge of the elastic body is farther than a periphery of the main body ofthe load cell from the male screw arranged at a center of the main body.46. The load cell attachment structure according to claim 8, wherein theelastic body is arranged at a periphery of the collar part.
 47. The loadcell attachment structure according to claim 8, wherein the washer partis larger in diameter than the load sensing part.
 48. A load cellattachment structure for attaching a load cell to an attachment plate,the load cell including a main body and a load sensing part, the loadcell attachment structure comprising: a first fastening part which isformed on the main body of the load cell; a second fastening part whichattaches the load cell to the attachment plate by engaging with thefirst fastening part; a washer part which entirely covers the loadsensing part, and is disposed between the load sensing part and theattachment plate; a collar part which is disposed between the washerpart and the second fastening part; and an elastic body which isdisposed between the washer part and the second fastening part, whereinthe elastic body is arranged at a periphery of the collar part, and alength of the collar part along an axis thereof is longer than athickness of the attachment plate.
 49. The load cell attachmentstructure according to claim 48, wherein the elastic body includes aninclination part.
 50. The load cell attachment structure according toclaim 48, wherein a second washer is disposed between the collar partand a nut included in the second fastening part.
 51. The load cellattachment structure according to claim 48, wherein the elastic bodyincludes a bending part.